The invention relates to apparatus for applying the decorative coating, or decorative film, of a transfer foil to a workpiece and, more particularly, to a machine for applying such a coating to the edge of a substrate which may be of quite intricate configuration.
The term "transfer foil", as used herein, refers to an article sometimes designated as "hot stamp tape", as in the U.S. patents to Dunning, U.S. Pat. Nos. 3,666,516, 3,953,635, and 4,007,067; or as "hot stamping foil" as in U.S. Pat. No. 4,084,032 to Pasersky.
The market place as well as the patent literature affords various pieces of equipment for applying transfer foil to a preshaped edge of a substrate.
Exemplary of such apparatus in the U.S. patent literature are the following: Billings U.S. Pat. No. 3,669,793 and Boettcher U.S. Pat. No. 4,118,264. The latter patent provides an informative discussion of the "hot stamping" method using "foil", as does a paper called "Hot Stamping: A Breakthrough in Wood Finishing Technology" by E. G. Robb, presented to Forest Products Research Society, Homewood, Illinois, October 1978.
In the cabinet and furniture industry, many doors, side panels and tops are presently made from materials, such as reconstituted fiber board, which are less costly and more available than solid or veneered woods, the exposed surfaces of the boards being finished in a manner which closely simulates a desirable natural wood grain finish in appearance.
The flat, planar surfaces of these panels, or boards, as well as the less complicated edges, such as the edges found on shelving or on other relatively simple profiles, can readily be coated with the desired decorative film of transfer foil capable of being dry bonded to the substrate by heat and pressure. Machines of several makes can perform this relatively simple type of edge coating with speed and precision.
Where complicated pre-shaped edges must be coated, however, the prior art devices have been plagued with problems, such as wrinkles, bubbles and bonding skips, or gaps, which not only detract from the appearance of the finished edge but from its desirable physical properties as well.
It is believed, in other words, that in the field of applying transfer foil to a complicated shaped edge of a substrate, there is considerable room for improvement.